30+ Best Web Developer Interview Questions [ FRESHERS ]

Last updated on 09th Nov 2021, Blog, Interview Questions

In a Web Developer interview, you can expect questions that assess both your technical and soft skills. For the technical portion, your Web Developer knowledge and skills will be put to the test. Employers may ask questions you can answer verbally, or you may be required to complete a whiteboard or coding problem. In whiteboard challenges, you will be given a code problem or task and asked to work out the problem and explain your solution.

1. Explain the key responsibilities of a Web Developer?

Ans: 

Key responsibilities of a web developer include:

• Program testing and debugging web applications
• Design, develop, test, and deploy applications.
• Updating sites for optimized server performance.
• Coordination with designers and programmers to develop projects.
• Fixing bugs, troubleshooting, and resolving issues
• Predicting and implementing periodic tests in case of system failure.
• Developing design patterns for web program optimization.
• Support and assist with best practices for website management.
• Take ownership of code throughout staging, development, testing, and deployment of the project in production.

2. What is CORA? Why is it so important?

Ans: 

Cross-Origin Resource Sharing (CORS) is defined as the browser mechanism that involves controlled resources access granted outside the given domain. It can enable a web page to access the resource with a different domain. It is a relaxation of some policies associated with browsers implemented on the same origin.

CORS is important because it follows the same-origin policy by channeling XMLHttpRequest and fetching JavaScript to make URL calls in the same location where the script is running. Without CORS, there will be restrictions in accessing some critical resources that power the web.

3. What is ETag, and how does it function?

Ans: 

An ETag is termed an opaque identifier that is usually allocated by the webserver. It is primarily used within the same version of the resources provided in the URL. ETag is an important part of HTTP and is responsible for reading client requests to notify whether to send the file (HTTP 200) or inform the client through a local copy (HTTP 304).

4. Enlist some of the latest form elements of HTML5.

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5. Explain what is the difference between cookies and local storage?

Ans: 

Cookies	session
Client Side/ Server Side	Data accessible both at client side and server side. The data is sent to the serverside with every cookie request.
Size	Storage capacity of cookies is 4095 bytes/cookie
Expiration	Cookies have expiration and cookie data gets deleted after some time

6. What web developer should know?

Ans: 

A good web developer should know

• HTML
• CSS
• SQL
• PHP/Ruby/Python
• JQuery
• JavaScript

7. Explain what is long polling?

Ans: 

Long polling is a web application development pattern used to emulate pushing data from the server to the client. When the long polling is used, the client sends a request to the server, and the connection remains intact until the server is ready to send data to the client. The connection will be closed only after the data is sent back to the client or connection timeout occurs.c

8. What are the types of CDNs supported in jQuery?

Ans: 

There are two widely used CDNs with jQuery:

• Microsoft: Used to load from jQuery AJAX CDN
• Google: Used to load jQuery from the Google libraries API

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9. What is the use of the $() function in jQuery?

Ans: 

The $() function is used as a wrapper to wrap objects into their jQuery counterparts. This is done to give users the ability to call any method that is defined for the jQuery object.

10. What are the advantages of using a content delivery network (CDN) in jQuery?

Ans: 

CDNs are widely used in jQuery as they offer an ample number of advantages for users.

• CDNs cause a significant reduction in the load for the server.
• They provide large amounts of savings in the bandwidth.
• jQuery frameworks load faster due to optimizations.
• CDNs have a caching ability that adds to quicker load times.

11. What is pair programming?

Ans: 

Pair programming is a scenario where you will be working closely with a colleague on the project, and this is done to help solve the problems at hand. If the development scenario is fast-paced, Agile development might not work efficiently. The interviewer asks this question to see if you can work with other people easily and effectively.

12. How can styles or classes be changed in elements using JavaScript?

Ans: 

JavaScript can be used to easily modify classes and styles in an element by making use of the following syntax:

13.What are the various data types present in JavaScript?

Ans: 

14. What is Event Bubbling?

Ans: 

Event bubbling is defined as the type of event propagation where the target element is first triggered. The triggering causes all the events of the child node to pass them to the parent node. The main reason for doing event bubbling is to get the speed since the code needs to traverse the DOM tree only once.

15. What is lazy loading?

Ans: 

Lazy loading is defined as a design pattern used in computer programming to delay the object initialization until a certain required period. Lazy loading is time-constrained since the code gets loaded when the user needs it. For instance, a button on a page directs to a different layout when it is clicked. Hence, there is no need for code loading for the initial layout. Besides, lazy loading contributes to the overall performance of a program if properly utilized.

16. What are some of the CSS3 transition properties?

Ans: 

Transition in CSS3 is very easy to use, and it provides rapid effects in terms of animation. Some of the main transition properties of CSS3 are:

• transition-delay
• transition-duration
• transition-property
• transition-timing-function

17. Why do we use DOCTYPE in HTML?

Ans: 

DOCTYPE in HTML denotes the instruction given to a web browser regarding the version of markup language. The web browsers understand the Document Type Definition (DTD) from the HTML document and provide some markup language rules so that the web browser can easily interpret the content correctly.

18. Why are media queries used in CSS3?

Ans: 

Media queries in CSS are used to define different media asset queries that are responsive and come in different varieties of shapes and sizes depending upon the viewer’s window. The entities may include height, width, viewport, resolution, orientation, etc.

19. What is the difference between XHTML and HTML?

Ans: 

XHTML	HTML
Tag should be in lowercase	It is not case sensitive
Tag should be closed once opened	Open-ended tags can be used
Attributes must be enclosed in double-quotes	Attributes must be enclosed in double-quotes

20.What are GET and POST? Explain what the difference between getting and posting is?

Ans: 

A GET request is generally used in the instances like AJAX calls to an API. GET requests are limited and secure. The user can easily view them if they have the URL.

A POST request is typically used to store data in a database submitted through a form. POST requests are more secure than getting requests. They have two steps to utilize the resource and remain hidden from the user.

21. What are CSS box model components?

Ans: 

The CSS box model components represent an entity under which HTML content is enclosed, like a box or a button element. Some of its components are:

Border: Denotes the content and padding around borders.

Content: Focuses on the actual displaying content.

Padding: Portrays space around the element.

Margin: Focused on the top layer of the box element.

22. Why is float used in CSS?

Ans: 

Float is a popular property in CSS to control the layout and position of an element on a web page.

Any element can be placed on the web page as per requirement. Consider the following example:

• div { float: right; }

Here, the contents of the div will be placed on the right side of the screen.

23. What is Webpack?

Ans: 

Webpack is a build tool that puts all of your assets, including Javascript, images, fonts, and CSS, in a dependency graph. Webpack lets you use require() in your source code to point to local files, like images, and decide how they’re processed in your final Javascript bundle, like replacing the path with a URL pointing to a CDN.

24. How does CSS3 help in implementing rounded borders easily?

Ans: 

CSS3 has the property that allows elements to be created with nice-looking rounded corners. This can easily be applied to all four sides or as per requirement.

The property has four attributes for four corners:

• border-top-left-radius
• border-top-right-radius
• border-bottom-left-radius
• border-bottom-right-radius

25. What is Responsive Web Design (RWD)?

Ans: 

Responsive web design is generally a concept of creating web pages that can be easily scaled across various resolutions without losing any information or screen tearing. The main concept of responsive web design is to deliver the structure of the web page that can be automatically adjusted across various platforms and devices with an optimal viewing experience.

26. How to Implement en queue and dequeue using only two stacks?

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Enqueue means to add an element, dequeue to remove an element.

27. What are some of the latest features of CSS3?

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CSS3 has brought tremendous changes ranging from making a more user-friendly framework and has to becoming powerful. Some of the latest features added CSS3 are:

• Animation enabled.
• Offers rounded corners to objects.
• Custom layout.
• Efficient placement of media queries.

28. What is Ajax? Enlist some of its utilities?

Ans: 

Asynchronous JavaScript XML or AJAX enables different applications to transport data to and from a server asynchronously without refreshing the web page. It simply ensures that some parts of the page are automatically updated without reloading the entire page to fetch new resources on the same page. AJAX can be implemented anywhere in the web application where small chunks of information can be retrieved or saved. This technology helps developers to create faster, efficient, and interactive web applications. Some of the utilities or benefits of AJAX are:

• Faster callback performance.
• Allows asynchronous calls to a web server.
• Improves web performance and usability.
• User-friendly, easy to understand, and implement.

29. What is the difference between localStorage and sessionStorage objects?

Ans: 

localStorage	sessionStorage
No expiry is there for stored data session	The object is valid for only a single
Data is not deleted upon the closure of the window	The object is immediately deleted upon closing the window

30. What is Node Package Manager or NPM?

Ans: 

NPM is a package manager for JavaScript. NPM is designed to put modules intact so that nodes when the need can find them. It is designed to maintain and serve conflicts arising in dependencies. It is mostly used to install programs, configure them, publish and develop them using the intact resources in the modules.

31. What is the difference between ‘==’ and ‘===’ operators?

Ans: 

Although both of the operators belong to the comparison operator category, the ‘==’ operator checks the given values, whereas the ‘===’ behaves like an equality operator and checks both the value and their type.

32. Enlist some tricks to reduce the load time of a web application.

Ans: 

Some of the most popular hacks to reduce load time are:

• Save the images as a compressed file so that image size can be optimized to screen resolution.
• Remove every JavaScript file to reduce mobile data.
• Minify and combine CSS and JS to call them in the footer.
• Switch to asynchronous JavaScript.

33. What is SVG and why is it used?

Ans: 

SVG stands for Scalable Vector Graphics. It is used to display vector-based graphics over the web. The graphical content it can render is based on an XML format. With SVG, the graphical content is of superior quality thereby providing the user with the ability to furnish high-quality images.

34. What are the features of Microservices?

Ans: 

Decoupling – Services within a system are largely decoupled. So the application as a whole can be easily built, altered, and scaled

Componentization – Microservices are treated as independent components that can be easily replaced and upgraded

Business Capabilities – Microservices are very simple and focus on a single capability

Autonomy – Developers and teams can work independently of each other, thus increasing speed

Continous Delivery – Allows frequent releases of software, through systematic automation of software creation, testing, and approval

Responsibility – Microservices do not focus on applications as projects. Instead, they treat applications as products for which they are responsible

Decentralized Governance – The focus is on using the right tool for the right job. That means there is no standardized pattern or any technology pattern.

Agility – Microservices support agile development. Any new feature can be quickly developed and discarded again

35. How do you do testing? And what do you think about this? How would you improve QA?

Ans: 

Good code means a less buggy web applications and fewer coding crises. A good web developer should value testing and respect the QA process, because it will cut down on the number of late nights where they try to find an issue which has been uncovered in the code.

36. Explain HTML 5, CSS3, JavaScript, and their importance in web development.

Ans: 

• HTML is a platform and browser independent markup language with a series of tags that provide the structure for a web page.
• CSS improves page layout and its contents with style.
• JavaScript controls the behavior of web elements, and thereby makes your website interactive/responsive, validates user input values, capture website visitor’s information and recognize previous visitors, help in analyzing the percentage of blog post visitors click-through rate.

37. List the differences between HTTP 1.1 and 2.0?

Ans: 

HTTP 1.1	HTTP 2
Request sent and responses received were in plain text format.	Messages both request and response are encapsulated in binary format, giving more protection from any unauthorized alterations.
Finds difficulty in handling whitespace, capitalization and line endings.	Use binary protocols that handle elements like whitespace, capitalization and line endings more efficiently
Needs more bandwidth to process the page contents	Consumes less bandwidth to display page contents
Prioritization of loading contents is not possible in HTTP 1.1	Developers have control over prioritizing / uploading content in the order of their preference.

38. Explain Pseudo class in CSS with examples?

Ans: 

Pseudo class in cascading style sheets is a keyword applied to HTML element’s selectors, to add special style on HTML events like onblur, onclick, onchange, onhover etc., in reference to external factors like previous website visit from navigation history, position or movement of the mouse, form element’s content status.

The syntax for Pseudo class:

Example:

39.How to integrate different stylesheets into a website?

Ans: 

It depends on the factor of how the site is laid out. However, for the most efficient performance, one file can be used with styles.css. If you want to change any style, open up the styles.css file, and in the relevant section, you can modify CSS. You can also link your HTML file through the below command.

40. What steps do you take to balance demanding client requirements?

Ans: 

A web developer may face unexpected challenges, including short turnaround times and overly-ambitious clients. Gaining a clear understanding of how a candidate handles this type of situation will help you understand their priorities and thought processes. What to look for in an answer:

• Performance under pressure
• Communication skills
• Commitment to releasing high-quality products

41. Tell Me What’s The Difference Between Standards Mode And Quirks Mode?

Ans: 

Quirks Mode is a default compatibility mode and may be different from browser to browser, which may result to a lack of consistency in appearance from browser to browser.

42. What Is The Main Advantage Of Loading Jquery Library Using Cdn?

Ans: 

This is a slightly advanced jQuery question. Well, apart from many advantages including reducing server bandwidth and faster download, one of the most important is that, if browser has already downloaded same jQuery version from the same CDN, then it won’t download it again. Since nowadays, many public websites use jQuery for user interaction and animation, there is a very good chance that the browser already has the jQuery library downloaded.

43. What is pagination? How can pagination be implemented?

Ans: 

Pagination is a simple sequence of pages in a website. These pages are interconnected and have similar content to display to users.

A simple example is the page selector on an e-commerce site that allows the users to browse through the products present on multiple pages rather than scrolling up and down on one single page.

It can easily be implemented in CSS3 using the following code:

44. What is z-index in CSS?

Ans: 

Z-index is a property in CSS that is used to define the order of elements on a web page. It works on the basis of order indices, where a higher-order element will appear before a lower-order element.

45. What are the added benefits of HTTP/2 compared to HTTP 1.1?

Ans: 

HTTP/2 has a number of notable advantages over HTTP 1.1, which are:

• Advanced server-push technology
• Reduced network footprint
• Uses network resources more effectively
• Eliminates security issues related to HTTP 1.1, such as a response splitting attack
• Enables superior capabilities, including effective TLS handling, prioritization, multiplexing, compression, and flow control.
• Compact command representation, which facilitates easier implementation and processing
• Robust and efficient data processing between server and client
• Improved throughput and lower network latency
• Less error-prone

46. What is an Entity Tag?

Ans: 

An Entity Tag, or ETag, is an integral element of HTTP (Hypertext Transfer Protocol) – the protocol that facilitates communication between servers and web browsers. Entity Tag is one of the many mechanisms that the Hypertext Transfer Protocol provides for cache validation, allowing conditional requests from a client.

47. What’s the difference between GET and POST?

Ans: 

GET	POST
If we are sending parameters in a GET request to the server, then those parameters will be visible in the URL, because in GET, parameters are append to the URL. So there’s a lack of security while uploading to the server.	If we are using POST then we are sending parameters in the body section of a request. If we send data after using encryption in the body of an http request, it’s quite a bit more secure.
We can only send a limited amount of data in a GET request, because the URL has its max limit and we can not append a long data string to the URL.	We can send a lot more data using POST.

48. What is Namespacing in JavaScript?

Ans: 

It is usually not a good practice to use global variables in programming languages including JavaScript. However, you may have to use global variables sometimes. So, JavaScript introduces the concept of namespacing which ties down a part of the code and registers it with a unique name.

The namespace is nothing more than a container name where we hold classes, functions, and variables that can be repeated with the same name in other namespaces or namespace without involving an error.

49. Which are the new APIs provided by HTML5?

Ans: 

The new APIs are –

• Media API
• Text track API
• Application cache API
• Data transfer API
• User interaction API
• Command API
• Constraint validation API
• History API

50. What is the difference between null value and undefined value in JavaScript?

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In JavaScript, undefined means a variable has been declared but has not yet been assigned a value. On the other hand, null is an assignment value. Undefined is a type whereas null is an object.

51. What does “use strict” do?

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The “use strict” is entered at the top of a JavaScript program. It assists in writing more secure JavaScript code by throwing an error if a global variable is accidentally created. For instance, the following piece of code will fail in its execution:

It will fail because x was not defined and is being assigned to a global variable, which is not permitted under “use strict.” This minor adjustment below resolves the error.

52. Explain the functionality of a browser?

Ans: 

• It helps access HTML pages and all web elements used in web-based applications, as well as websites, and display responses from other sites as an answer to the requests.
• Allows web search for the site of your interest by entering URL or web address in the address bar and view response by using any of the search engines.
• Navigation controls are used for going back to recently opened pages by clicking the back button and next button to move forward.
• History keeps track of the visited sites in chronological order. It allows remembering or bookmarking sites of your interest to refer or explore at a later stage. It also saves previously visited sites in the form of cache and make visitor recognized by sites, making access to those sites quicker.
• Manages passwords for frequently used websites requiring authentication and in most cases keep users already logged into the account.
• Allows accessing various sites, exchanging information via API calls, communication via email, data, and media file-sharing software.

53. What configuration and setup is required for sending emails via your website?

Ans: 

Ideally you can configure your SMTP on a single server using a third-party service like Gmail SMTP, or use elastic email, using hostname, port, username, and password.

54. How to improve the user experience for users visiting your website?

Ans: 

• Your website/application should be running 24×7.
• It should handle multiple user access load during peak time or season.
• It should be user friendly, and easy to navigate to the features that the visitor is looking for.
• Should have engaging videos to introduce your product features.
• The website should be searched from search engines based on keywords entered.
• The website should be integrated with a payment gateway with all possible alternatives for transactions.
• Should have free to use features available for users to decide on buying your product.
• User data should be secured while accessing the website.
• Sessions and cache features should recognize returning visitors.

55. Explain with examples, differences between Canvas and SVG?

Ans: 

Canvas and SVG both containers are used to store graphics in the HTML page, however, they have the following differences between them.

SVG	Canvas
< svg > is a container element for graphics like box, circle, ellipse etc in HTML page	< canvas > is container for drawing graphics using javascript
SVG is scalable and suitable for high resolution printing.	Canvas is not scalable and are not suitable for high resolution printing.
Display better performance loading small number of objects and large surface objects.	Display better performance loading large number of objects and small surface object.
SVG can be modified by script and css	Canvas can be modified only with script.

56. When should you use id and class selector?

Ans: 

ID as a selector is defined to uniquely identify it as an element, hence there should not be same ID applied to any other element within the same page. Whereas class selectors are types of CSS selectors that are applied in order to add style to that element, for example, font family, font size, or color, hence class selectors can be applied to multiple elements.

57. Explain a non-functional requirement and a functional one?

Ans: 

A non-functional requirement describes a system’s type (accessibility, maintainability, security). Whereas a functional requirement describes the specific functionality of that system.

58.Which Basic Technical Skills Are Required To Be A Front-End Developer?

Ans: 

• HTML
• CSS
• JavaScript
• JQuery

59. Write a function to compute the Nth Fibonacci number.

Ans: 

The following code block is borrowed from Geeksforgeeks. It gives a good example.

In C++:

• //Fibonacci Series using Recursion
• #include
• using namespace std;
• int fib(int n)
• {
• if (n <= 1)
• return n;
• return fib(n-1) + fib(n-2);
• }
• int main ()
• {
• int n = 9;
• cout << fib(n);
• getchar();
• return 0;
• }

60. What is the advantage of collapsing white space?

Ans: 

White spaces are blank sequences of space characters, which is treated as a single space character in HTML. The browser collapses multiple spaces into a single space, so we can indent lines of text without worrying about multiple spaces. This enables us to organize the code into a much more readable format.

61. By which mechanism in JavaScript can you detect the operating system on a client machine?

Ans: 

The operating system on a client system can be known by using the JavaScript property navigator.appVersion

62. What is the difference between window.onload and on document ready?

Ans: 

The window.onload event will not trigger until every single element on the page has been fully loaded, including CSS, images and/or other assets. The main disadvantage is that it might take a while before any code is actually executed. On the other hand, on document ready executes code as soon as DOM is loaded.

63. What tools do you use to find a performance bug?

Ans: 

64. What is Signal Topology?

Ans: 

Signal topology is the mapping of different nodes in a network based on the paths by which the signals pass through. Signal topology generally refers to the actual path that the signals (e.g., electromagnetic, electrical, optical, etc.) take when propagating between nodes.

65. In Signal Topology which materials we use to connect nodes?

Ans: 

Signal topology is the mapping of different nodes in a network based on the paths by which the signals pass through. Signal topology generally refers to the actual path that the signals (e.g., electromagnetic, electrical, optical, etc.) take when propagating between nodes.

66. Who & in which year introduced www?

Ans: 

The whole idea of www was introduced in 1989 by Sir Tim Berners-Lee, who is considered as the father of the internet. Since then the growth of the internet was rapid. Tim Berners-Lee himself introduced the terms like URL, HTTP. He is currently the chairman of W3C which is the governing body of the web.

67.What is event delegation and how does it work?

Ans: 

Event delegation allows us to avoid adding event listeners to specific nodes of the DOM; instead, the event listener is added to one parent. Using event delegation it’s possible to add an event handler to an element, wait for an event to bubble up from a child element and easily determine from which element the event originated.

68. What’s the best way to integrate 5 different stylesheets into a website?

Ans: 

It usually depends on how the site is laid out. However, in most cases combining the stylesheets into a single one is the best approach. You can use Gulp to do so.

69. What’s the difference between standards mode and quirks mode?

Ans: 

Quirks Mode	Standards Mode
In quirks mode, layout emulates nonstandard behavior in Navigator 4 and Internet Explorer 5.	In standards mode, the behavior is (hopefully) the behavior described by the HTML and CSS specifications.
This is essential in order to support websites that were built before the widespread adoption of web standards.	In almost standards mode, there are only a very small number of quirks implemented.

70. What are the benefits of using the Internet?

Ans: 

71. What are the Http methods?

Ans: 

72. What is an ID selector?

Ans: 

The ID selector uses the “ID” attribute of the target HTML element to select it. The constraint to work is that the ID should be unique within a page so that the selector can point it out correctly.

To build an ID selector expression, start with a hash (#) character, followed by the id of the element.

Here is an example which selects a paragraph element using its ID.

#sample {padding: 10px;}

…

73. What are the core data types available in JavaScript?

Ans: 

74. What is Scope in JavaScript?

Ans: 

The general meaning of scope is the accessibility of functions and variables in an application. Usually, we use them in two ways, i.e., Local and Global.

a) Local Scope

• If we declare a function or variable inside a function, then we can access it only inside that function.

b) Global Scope

• Declaring a variable anywhere on the page would mean that we can access it from any of the functions on that page.

75. What does the operator do in JavaScript?

Ans: 

The operator give back the type of a variable in the form of a string.

76. Differentiate Between CDATA And PCDATA In DTD?

Ans: 

CDATA	PCDATA
It is an Unparsed Character Data, and the CDATA is used about text data that shouldn’t be parsed by the XML parser.	It is a Parsed Character Data. XML parsers will parse all the text in the XML document.

77. Can You List Some Of The Types Of CSS That Are Used?

Ans: 

External CSS: These are used to import an external CSS file into the HTML document.

Inline CSS: It supports the addition of CSS inline, along with HTML elements.

Embedded CSS: It is mainly used to add the CSS styles by using the attribute.

78. Tell Me Something About HTTP/3?

Ans: 

HTTP/3 can be defined as a major revision of the (HTTP) Hypertext Transfer Protocol, and It is a technology that underpins the transfer of data on the web. HTTP/3 runs over QUIC – It is an encrypted general-purpose transport protocol that will multiplex various streams of data on one single connection.

79. How To Link Images And Files On The Web?

Ans: 

There are two ways of linking files and images on the Web:

1.Absolute links have the full URL, and all directory information is encoded in the link.

Relative links relate where the current page is to where the image or document is located.

80. What Is Pagination?

Ans: 

Pagination can be used in almost every web application to divide the returned data and display it on various pages within a single web page. Pagination includes the logic of preparing and displaying the links to the different pages. Pagination is handled client-side or server-side.

81. Define Type Coercion In JavaScript?

Ans: 

Type Coercion is referred to as the technique of automatic or implicit conversion of values from one data type to another data type. It also includes conversion from Number to String, Boolean to Number, String to Number, etc., when various types of operators are applied to the values.

82. What’s the biggest difference between developing for mobile and desktop?

Ans: 

Most people browse on mobile, but the majority of development work happens on a desktop. A suitable candidate should know how to develop for both, and they should be able to sound off on crucial differences, such as screen size, touch input, limited multitasking, and variation in browser plug-ins. They should also understand how to create a great user experience on any platform.

83. What’s the difference between ES5 and ES6?

Ans: 

This question could have multiple answers. It will help to know a few of them and list them to the interviewer:

• ES5 and ES6 are both versions of JavaScript. ES6 is the most recent and was introduced in 2015.
• ES6 has the same data types as ES5 but also added the new symbol data type.
• To define a variable in ES5, you use the var keyword. The var keyword is still available in ES6, but it’s recommended to use either const or let.
• In ES5, you must define a function using the function keyword. In ES6, you can use an arrow function to define a function without using the keyword.
• ES6 added destructuring functionality to ES5, making objects easier to handle.

84. Describe Coffee Script?

Ans: 

CoffeeScript is a little programming language that compiles into JavaScript. It is an attempt to use the best parts of Javascript in a simple way. It also helps developers to write JavaScript code better by presenting the user with a more consistent syntax and skirting the unusual nature of JavaScript language.

85. What is a callback function?

Ans: 

A callback function is a function passed into another function as an argument, which is then invoked inside the outer function to complete some kind of routine or action.

86. Explain what is the difference between Class and Prototypal inheritance in Javascript?

Ans: 

Inheritance in JavaScript is different from most other programming languages. The object system in JavaScript is prototype based, not class based. Objects in JavaScript are just a collection of a name (key) and value pairs. When it comes to inheritance, JavaScript only has one construct: objects. Every object has a private property which contains a link to another object called its prototype.

87. Can you tell us what are the benefits of CoffeeScript over JavaScript?

Ans: 

• Easily understandable − CoffeeScript is a shorthand form of JavaScript, its syntax is pretty simple compared to JavaScript. Using CoffeeScript, we can write clean, clear, and easily understandable codes.
• Write less do more − For a huge code in JavaScript, we need comparatively very less number of lines of CoffeeScript.
• Reliable − CoffeeScript is a safe and reliable programming language to write dynamic programs.
• Readable and maintainable − CoffeeScript provides aliases for most of the operators which makes the code readable. It is also easy to maintain the programs written in CoffeeScript.
• Class-based inheritance − JavaScript does not have classes. Instead of them, it provides powerful but confusing prototypes. Unlike JavaScript, we can create classes and inherit them in CoffeeScript. In addition to this, it also provides instance and static properties as well as mixins. It uses JavaScript’s native prototype to create classes.
• No var keyword − There is no need to use the var keyword to create a variable in CoffeeScript, thus we can avoid accidental or unwanted scope deceleration.
• Avoids problematic symbols − There is no need to use the problematic semicolons and parenthesis in CoffeeScript. Instead of curly braces, we can use whitespaces to differentiate the block codes like functions, loops, etc.
• xtensive library support − In CoffeeScript, we can use the libraries of JavaScript and vice versa. Therefore, we have access to a rich set of libraries while working with CoffeeScript.

88. Describe what is a Thread-Local object in Python Flask?

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A thread-local object is an object that is stored in a dedicated structure, attached to the current thread id. Flask utilizes thread local objects internally so that user don’t have to pass objects around from function to function within a request to stay threadsafe. Thread local storage performs within the current thread. This approach is helpful, but it needs a valid request context for dependency injection or when attempting to reuse code which utilizes a value pegged to the request.

89. Explain the syntax and how to use a Function as A Class?

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90. Explain how you deal with browser-specific style incompatibility?

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There are multiple ways to work around this. The simplest way to proceed would be to utilize a conditional statement in the head tag of your HTML. In this way, you can recognize the browser and load an external stylesheet.

91. What is the difference between React Native and React?

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• React is a Javascript library that is used to build the UI interface as front-end web and being run on the server. React native is an extension of React. React Native allows us to create native mobile applications i.e iOS, Android and windows and it can also be used in existing mobile applications.

92. What is server-side development?

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Server-side development is popularly known as back-end development. The server-side development deals with pieces of code that runs on the server dealing with generation of content of web page. Some examples of server-side programming include querying and operating the database, access and write on a server, interact with other servers etc. Some of the popular backend languages are PHP, C++, Python among others.

93. What web browser do you prefer?

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• A good web developer understands it is crucial to design a website that looks good in all browsers (including mobile browsers), and on all screens.
• This is exactly what you should focus on in your answer, saying that you prefer one of the browsers (perhaps Chrome for their tools for Web Developers), but design websites that work well with all browsers and screens.

94. How Would You Ensure That Your Web Design Or App Is User-Friendly And Accessible?

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A front-end developer should have a strong command over usability and accessibility while designing experiences for end-users. This question will provide the interviewer with an insight into your knowledge of these standards and web development best practices.

To answer this question, you should talk about your first-hand experience in implementing usability and accessibility standards. Discuss your drive to create a web experience that’s accessible to all end users. Talk about ways in which you have implemented usability and accessibility in your previous front-end development projects.

For instance, you can say “I test my web applications on various browsers and devices to verify that the experience is user-friendly. I also utilize familiar screen reading software and other assistive solutions to check it’s accessibility.”

95. What is the web development architecture?

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The whole scenario starts with a user opening any web application over the internet. The user then triggers a request to the web server. The transfer happens with the use of protocols like HTTP, FTP etc. We will study more about protocols later in the article. The web server forwards the request to the web application server according to the generated request. The web application server processes the request and generates an appropriate response. There will be an interaction with the database layer if the data is required to be stored for future use. The result is sent to the web server with the processed data as a response. Web server responds back to the client. The output is shown on the front-end.

96. Explain big-O notation in the simplest terms.

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The big-O notation tells how fast an algorithm is. This is very important whether you are evaluating other people’s algorithms or your own.

Big-O notation, also known as Landau’s symbol, tells how the runtime or space requirement of a function grows as the input grows. Which means that the algorithm speed isn’t measured in seconds but in the growth of the number of operations.

97. Why is it a good long-term play idea to split coding and styling?

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While the official line on this is to be able to keep a more consistent look and feel regarding a particular project, a more basic reason for it is “something you don’t have to do yourself.” For example: Say it’s been several years since a site went live and Management feels like it’s due for a refresh. As long as most of the individual pages stick to the rules you’ve specified in the CSS, this means that color, fonts, images and in some cases complete layouts across the entire site can be changed without you having to ever having to get involved.

98.What are your feelings on Java and/or Flash?

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Okay, yes, time for the elephant in the room. Yes, both were incredibly powerful and influential down to this day. Between the two of them, however, they are responsible for serious effects on the Web as a whole and are just not capable of holding pride-of-place as they once did.

99. What happens when you go to a website on a browser and hit enter?

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This is by far the most popular question we have seen. It’s a great question because it gives you the opportunity to showcase both specific and general knowledge in web development. Try to be detailed in your answer, especially in your area of expertise (front-end, back-end, networking, etc.).

The following list below are the important steps to remember when answering this question. We recommend that you go into more detail in your area of expertise.

• DNS Lookup: You should mention that the browser will look for the IP address of the URL (either in the cache, or doing a DNS query).
• TCP connection: You should talk about how the browser initiates a TCP connection (HTTP is a protocol that utilizes a TCP connection). There is a handshake that happens between the client (browser) and the server. If you have knowledge of HTTPS vs. HTTP, this is a good time to mention how they differ. If you have knowledge of sockets, you can elaborate more on the details of the connection and the ports that are commonly used (HTTP uses port 80 and HTTPS uses port 443). You can read more about HTTP here.
• HTTP request: This is where you mention that going to a website on a browser is a GET request. It’s also a good time to talk about what information is sent with a request (headers (cookies, cache headers), URL (query parameters), etc.)
• HTTP response: Depending on your knowledge of web servers, you can go into a lot of depth here talking about how a web server works and responds to a request (load balancers, API gateways, request handlers, etc.). You should then mention the type of responses the request can have (status codes, formats (HTML, JSON, XML, etc.)).
• Browser displays HTML: This is a step that is often ignored. For strong front-end developers, you want to use this opportunity to discuss what happens when the browser gets the HTML content. You should talk about how the HTML gets inserted into the DOM, and how there may be subsequent requests for CSS, Javascript files, etc.